The following is a tabulation of some of the prior art that presently appears relevant:
U.S. patents4,496,283Jan. 29, 1988Kodric4,729,716Mar. 8, 1988Schmidt4,818,180Apr. 4, 1989Lin5,086,664Feb. 11, 1992Wagner6,016,015Jan. 18, 2000WillardU.S. Pat. No. 6,853,096 B1Feb. 8, 2005YuU.S. Pat. No. 6,883,399 B2Apr. 26, 2005BurstallU.S. Pat. No. 6,942,454 B2Sep. 13, 2005OhlmannU.S. Pat. No. 7,453,167 B2Nov. 18, 2008GilbertU.S. Pat. No. 7,931,440 B2Apr. 26, 2011BobowickU.S. Pat. No. 7,963,112 B1Jun. 21, 2011JosephU.S. Pat. No. 8,177,481 B2May 15, 2012LiangU.S. Pat. No. 8,341,957 B2Jan. 1, 2013Joseph
U.S. Patent PendingUS 2008/0047270 A1Feb. 28, 2008GilbertUS 2009/0035134 A1Feb. 5, 2009KuoUS 2009/0066088 A1Mar. 12, 2009LiangUS 2009/0220342 A1Sep. 3, 2009WuUS 2009/0284018 A1Nov. 19, 2009EllisUS 2010/0143133 A1Jun. 10, 1010BobowickUS 2011/0175370 A1Jul. 21, 2011DugasUS 2011/0200436 A1Aug. 18, 2011WuUS 2012/0121379 A1May 17, 2012ChioUS 2012/0074705 A1Mar. 29, 2012StephensUS 2012/0061972 A1Mar. 15, 2012YoungUS 2013/0177426 A1Jul. 11, 2013AndreuUS 2014/0265598 A1Sep. 18, 2014Isabella